The invention is narrowly directed to help a baseball pitcher choose and use the most basic training device rather than choosing one of numerous pitching targets which provide indicia of accuracy or scoring, or choosing a device which uses a net or a canvas attached to a rectangular frame.
Devices for scoring pitches are generally directed to fill special needs, serve a specified narrow purpose, are too complicated for use by a typical youngster bent on honing his pitching skill, and too expensive to purchase and to maintain. Most popular among passive devices which do nothing more than attempt to return, deflect or stop a ball pitched onto a target area, is a net or a canvas either held directly in a frame, usually rectangular, or by plural springs provided with a back support; preferably the ground-contacting portion of the frame is anchored to the ground by plural stakes and not free-standing.
The problem with using a net is that the velocity and direction of return of the ball is highly variable depending on how close to the frame the net is struck by the ball. The variation in the angle of return is exaggerated when the face of the net is tilted at an obtuse angle, with the result that the ball is seldom returned to the vicinity of the pitcher. Moreover, a ball striking the frame careens off unpredictably, thus jeopardizing the safety of bystanders. Though the basic, simple, net or canvas tilted at an obtuse angle could be constructed of heavy duty materials held in a rigid frame by plural springs able to withstand repeated impacts of a baseball, the variability of rebound caused by loosening of the springs and net after multiple impacts is as unavoidable as it is undesirable because it shortens the useful life of the device.
The goal is to provide an unobviously simple, durable, passive, planar, solid target which is light-weight so as to be portable and stowable; which is not a net yet fulfills the needs of a lone pitcher practicing with a limited supply of baseballs, typically in the range from 1 to 5, so that with a large enough target resting directly on the ground, the time spent chasing pitched balls is limited only to those balls which entirely miss the target. In one embodiment all pitches hitting the target are returned in the general vicinity of the target, mimicking a “bunt”, irrespective of where they strike the target. In another embodiment, the goal is to provide a target which strives to return a pitch striking any portion of its surface at a velocity of at least 100 Km/hr (62 mph), to a zone in the general vicinity of the pitcher, “strikes” being returned closer to the pitcher by virtue of the smaller reflected angle (relative to the horizontal) from the strike zone than a pitch in the upper periphery of the target around the strike zone; alternatively, by choice of the resilience of materials used in the strike zone and in the peripheral zone, a “ball” may be returned closer to the pitcher than a “strike”; and, using each embodiment of the invention, the surface of each returned ball bears no visually noticeable damage due to its impact on the target. It is essential that the entire practice device be an essentially weatherproof, easily portable composite which is stowable in the trunk of an automobile referred to as a “compact”, and weighs in the range from 5-15 Kg (11-33 lb); and despite its light weight militating against maintaining a fixed position when struck with a ball pitched at a velocity in the range from about 100 km/hr (62 mph) to about 160 km/hr (99 mph), the target with a minimum of support structure is to remain stable and immovable in use.
When the resilience of the resilient pad is low as measured by ASTM D1667, pitches are returned as bunts; when the resilience of the pad is relatively higher so as to complement the rebound imparted by a cover sheet tightly tensioned across it, pitches are returned as infield hits. In each case, the pad being backed by a relatively thin, indentable, impact-resistant backstop with defined flexibility, a ball pitched against the resilient pad at a velocity in excess of about 100 km/hr (62 mph) makes a momentary indentation (hence “indentable”) in all three components, the cover sheet, the pad and the backstop. Though such an indentation is minimal relative to the indentation made in a net adapted to return a baseball pitched at the same speed, the combination of physical properties of each structural component and indentation of all three, together with the angulation of the target's surface, is sufficient to bias the return vector (representing the ball) towards the central horizontal axis so as to “serve” the pitch to a chosen location in front of the pitcher. Over a distance of about 18.3 meters (60 feet) the biased return vector delivers the ball closer to the pitcher than the reflected vector.
When the resilient pad is a composite of two pads having markedly different resilience, one central pad dimensioned to correspond to the strike zone and the other pad for the peripheral zone, the pitcher can get a physical confirmation of a strike by choosing the appropriate resilience of each of the pads. The returned distance of a “strike” may be less than or greater than that of a “ball” depending upon whether the choice of the resilience of the central pad, which resilience determines the rebound of the ball, is higher or lower than that of the peripheral pad.
U.S. Pat. No. 3,001,790 to Pratt teaches a simple practice device for a baseball pitcher using a target of wood, plastic, metal or concrete panels, the central panel of the target being vertical and planar, and beveled peripheral panels around the central panel being angulated so that a pitch is returned in a direction dictated by the angle of the panels, only pitches in the central panel being returned along a path towards the pitcher.
The foregoing '790 patent was an improvement upon an earlier relatively complicated practice device disclosed in U.S. Pat. No. 2,162,438 to Letarte, in which plural panels rebound a pitched ball in various directions, the panels imparting different rebounds to balls in accordance with the speed at which each panel is struck, and depending upon which panel is struck. Angulation of a central panel which is covered with resilient material is adjustable so as to present a face at an obtuse angle. Angulation of hinged panels is controlled by an elaborate support structure. The panels may be constructed of wood, metal or other suitable material which will impart a substantial rebound to the ball but there is no enabling disclosure to help choose what physical properties might be critical to provide a particular rebound, namely sufficient to return the ball to a zone in the general vicinity of the pitcher. Recognizing that a concrete surface will provide a baseball pitched against it with substantial rebound, there is no suggestion that the material of choice might itself be resilient enough to be indentable by a baseball striking the material's surface at a velocity of at least 100 km/hr (62 mph). That the material itself is rigid is implicit from the disclosure that the panels are covered with a resilient material to provide the requisite rebound, e.g. a sheet of rubber which is of sufficient thickness to impart rebound to the baseball at a comparatively fast speed when thrown against the target; and again there is no teaching to enable one to find a suitable sheet of rubber, or its thickness, for the specified purpose, or the manner in which it is overlaid on the suitable material, without undue experimentation.
Further, the accuracy of a pitch to the '438 device is determined automatically by the nature of the rebound of the ball, that is, by the angular direction of a returned ball, since the strike zone is fixed by the choice of size of the central panel. Moreover, metal hinges for the panels interfere with the angle of return of the baseball even after their usefulness is impaired by repeatedly being struck by a baseball; and though the stability of the several panels relies upon the size of the large panels which stand at the same height as the batter, the stability is compromised because the lower edges of the panels are not supported on the ground. Much as the '790 patent sought to eliminate the complexities and disadvantages of the '438 invention, and presumably its expected heavy weight, the use of man-made materials not available in nature, in the invention disclosed herein, which materials have the physical properties specified, seeks to improve on the invention disclosed in the '790 patent.